Most of what a devops person does is in fact development but it is of the non value adding variety. Basically a devops person spends the vast majority of their time configuring common off the shelf software, scripting this or that, etc.
A singular matrix is a matrix which has no inverse because its determinant is zero. If you recall, the inverse of a matrix is. 1/ ad-bc multiplied by: [ d -b ] [-c a ] If ad-bc = 0, then the inverse matrix would not exist because 1/0 is undefined, and hence it would be a singular matrix. E.g.
Matrix (mathematics) In mathematics, a matrix (plural matrices) is a rectangular array of numbers, symbols, or expressions, arranged in rows and columns. For example, the dimensions of the matrix below are 2 Ã 3 (read two by three), because there are two rows and three columns: [ 1 9 â 13 20 5 â 6 ].